This arrangement, which can be used in a data modem (modulator-demodulator) and preferably in a data receiver, permits of providing the modem or the receiver with a generator of a clock signal (time base signal) whih is synchronous with the received data and has the form of a rectangular signal whose positive transitions can be used especially for sampling the data signal, which permits of regenerating this data signal. The invention is preferably used for low-speed voiceband data transmission, the binary rate (modulation rate) preferably being equal to or less than 4800 Bauds.
A known solution, frequently adopted to obtain bit synchronization in an asynchronous transmission mode, consists in utilizing a digital bit synchronization circuit. It is difficult to employ this arrangement for the type of modem considered because it is then necessary to use a quartz time base and a plurality of logic circuits and bistable circuits. Such a solution gives a high performance, but it is bulky, complex and not very economical for the type of application required; in fact, it is addressed to high-performance modems (high speed), for which in virtue of the CCITT standards a very high transmission stability (precision in frequency, for rates above 1200 Bauds, of the order of 10.sup.-4 and use of the LSI technology) is required, whereas the invention rather aims at low and medium speed modems (rates less than or equal to 4800 Bauds), for which the quartz time base may be replaced by an RC oscillator, a precision of frequency of 0.5% being sufficient for the reception.